/**
 * Copyright (C) 2010-2013 Alibaba Group Holding Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.alibaba.rocketmq.remoting.netty.server;

import com.alibaba.rocketmq.remoting.ChannelEventListener;
import com.alibaba.rocketmq.remoting.InvokeCallback;
import com.alibaba.rocketmq.remoting.RPCHook;
import com.alibaba.rocketmq.remoting.RemoteServer;
import com.alibaba.rocketmq.remoting.common.Pair;
import com.alibaba.rocketmq.remoting.common.RemoteHelper;
import com.alibaba.rocketmq.remoting.common.RemoteUtil;
import com.alibaba.rocketmq.remoting.exception.RemoteSendRequestException;
import com.alibaba.rocketmq.remoting.exception.RemoteTimeoutException;
import com.alibaba.rocketmq.remoting.exception.RemoteTooMuchRequestException;
import com.alibaba.rocketmq.remoting.netty.NettyDecoder;
import com.alibaba.rocketmq.remoting.netty.NettyEncoder;
import com.alibaba.rocketmq.remoting.netty.NettyRemoteAbstract;
import com.alibaba.rocketmq.remoting.netty.NettyRequestProcessor;
import com.alibaba.rocketmq.remoting.netty.event.NettyEvent;
import com.alibaba.rocketmq.remoting.netty.event.NettyEventType;
import com.alibaba.rocketmq.remoting.protocol.RemoteCommand;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.PooledByteBufAllocator;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.timeout.IdleState;
import io.netty.handler.timeout.IdleStateEvent;
import io.netty.handler.timeout.IdleStateHandler;
import io.netty.util.concurrent.DefaultEventExecutorGroup;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.net.InetSocketAddress;
import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicInteger;


/**
 * Remoting服务端实现
 *
 * @author shijia.wxr<vintage.wang@gmail.com>
 * @since 2013-7-13
 */
public class NettyRemoteServer extends NettyRemoteAbstract implements RemoteServer {
    private static final Logger log = LoggerFactory.getLogger(RemoteHelper.RemotingLogName);
    private final ServerBootstrap serverBootstrap;
    private final EventLoopGroup eventLoopGroupWorker;
    private final EventLoopGroup eventLoopGroupBoss;
    private final NettyServerConfig nettyServerConfig;
    // 处理Callback应答器
    private final ExecutorService publicExecutor;
    private final ChannelEventListener channelEventListener;
    // 定时器
    private final Timer timer = new Timer("ServerHouseKeepingService", true);
    private DefaultEventExecutorGroup defaultEventExecutorGroup;

    private RPCHook rpcHook;

    // 本地server绑定的端口
    private int port = 0;


    public NettyRemoteServer(final NettyServerConfig nettyServerConfig) {
        this(nettyServerConfig, null);
    }


    public NettyRemoteServer(final NettyServerConfig nettyServerConfig,
                             final ChannelEventListener channelEventListener) {
        super(nettyServerConfig.getServerOnewaySemaphoreValue(), nettyServerConfig
                .getServerAsyncSemaphoreValue());
        this.serverBootstrap = new ServerBootstrap();
        this.nettyServerConfig = nettyServerConfig;
        this.channelEventListener = channelEventListener;

        int publicThreadNums = nettyServerConfig.getServerCallbackExecutorThreads();
        if (publicThreadNums <= 0) {
            publicThreadNums = 4;
        }

        this.publicExecutor = Executors.newFixedThreadPool(publicThreadNums, new ThreadFactory() {
            private AtomicInteger threadIndex = new AtomicInteger(0);


            @Override
            public Thread newThread(Runnable r) {
                return new Thread(r, "NettyServerPublicExecutor_" + this.threadIndex.incrementAndGet());
            }
        });

        this.eventLoopGroupBoss = new NioEventLoopGroup(1, new ThreadFactory() {
            private AtomicInteger threadIndex = new AtomicInteger(0);


            @Override
            public Thread newThread(Runnable r) {
                return new Thread(r,
                        String.format("NettyBossSelector_%d", this.threadIndex.incrementAndGet()));
            }
        });

        this.eventLoopGroupWorker =
                new NioEventLoopGroup(nettyServerConfig.getServerSelectorThreads(), new ThreadFactory() {
                    private AtomicInteger threadIndex = new AtomicInteger(0);
                    private int threadTotal = nettyServerConfig.getServerSelectorThreads();


                    @Override
                    public Thread newThread(Runnable r) {
                        return new Thread(r, String.format("NettyServerSelector_%d_%d", threadTotal,
                                this.threadIndex.incrementAndGet()));
                    }
                });
    }


    @Override
    public void start() {
        this.defaultEventExecutorGroup = new DefaultEventExecutorGroup(//
                nettyServerConfig.getServerWorkerThreads(), //
                new ThreadFactory() {

                    private AtomicInteger threadIndex = new AtomicInteger(0);


                    @Override
                    public Thread newThread(Runnable r) {
                        return new Thread(r, "NettyServerWorkerThread_" + this.threadIndex.incrementAndGet());
                    }
                });

        ServerBootstrap childHandler = //
                this.serverBootstrap.group(this.eventLoopGroupBoss, this.eventLoopGroupWorker)
                        .channel(NioServerSocketChannel.class)
                                //
                        .option(ChannelOption.SO_BACKLOG, 1024)
                                //
                        .option(ChannelOption.SO_REUSEADDR, true)
                                //
                        .option(ChannelOption.SO_KEEPALIVE, false)
                                //
                        .childOption(ChannelOption.TCP_NODELAY, true)
                                //
                        .option(ChannelOption.SO_SNDBUF, nettyServerConfig.getServerSocketSndBufSize())
                                //
                        .option(ChannelOption.SO_RCVBUF, nettyServerConfig.getServerSocketRcvBufSize())
                                //
                        .localAddress(new InetSocketAddress(this.nettyServerConfig.getListenPort()))
                        .childHandler(new ChannelInitializer<SocketChannel>() {
                            @Override
                            public void initChannel(SocketChannel ch) throws Exception {
                                ch.pipeline().addLast(
                                        //
                                        defaultEventExecutorGroup, //
                                        new NettyEncoder(), //
                                        new NettyDecoder(), //
                                        new IdleStateHandler(0, 0, nettyServerConfig
                                                .getServerChannelMaxIdleTimeSeconds()),//
                                        new NettyConnectManageHandler(), //
                                        new NettyServerHandler());
                            }
                        });

        if (nettyServerConfig.isServerPooledByteBufAllocatorEnable()) {
            // 这个选项有可能会占用大量堆外内存，暂时不使用。
            childHandler.childOption(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT);
        }

        try {
            ChannelFuture sync = this.serverBootstrap.bind().sync();
            InetSocketAddress addr = (InetSocketAddress) sync.channel().localAddress();
            this.port = addr.getPort();
        } catch (InterruptedException e1) {
            throw new RuntimeException("this.serverBootstrap.bind().sync() InterruptedException", e1);
        }

        if (this.channelEventListener != null) {
            this.nettyEventWorker.addEventListener(channelEventListener).start();
        }

        // 每隔1秒扫描下异步调用超时情况
        this.timer.scheduleAtFixedRate(new TimerTask() {

            @Override
            public void run() {
                try {
                    NettyRemoteServer.this.scanResponseTable();
                } catch (Exception e) {
                    log.error("scanResponseTable exception", e);
                }
            }
        }, 1000 * 3, 1000);
    }


    @Override
    public void registerProcessor(int requestCode, NettyRequestProcessor processor, ExecutorService executor) {
        ExecutorService executorThis = executor;
        if (null == executor) {
            executorThis = this.publicExecutor;
        }

        Pair<NettyRequestProcessor, ExecutorService> pair =
                new Pair<NettyRequestProcessor, ExecutorService>(processor, executorThis);
        this.processorTable.put(requestCode, pair);
    }


    @Override
    public void registerDefaultProcessor(NettyRequestProcessor processor, ExecutorService executor) {
        this.defaultRequestProcessor = new Pair<NettyRequestProcessor, ExecutorService>(processor, executor);
    }


    @Override
    public RemoteCommand invokeSync(final Channel channel, final RemoteCommand request, final long timeoutMillis)
            throws InterruptedException, RemoteSendRequestException, RemoteTimeoutException {
        return super.invokeSyncImpl(channel, request, timeoutMillis);
    }


    @Override
    public void invokeAsync(Channel channel, RemoteCommand request, long timeoutMillis, InvokeCallback invokeCallback)
            throws InterruptedException, RemoteTooMuchRequestException, RemoteTimeoutException, RemoteSendRequestException {
        super.invokeAsyncImpl(channel, request, timeoutMillis, invokeCallback);
    }


    @Override
    public void invokeOneway(Channel channel, RemoteCommand request, long timeoutMillis)
            throws InterruptedException, RemoteTooMuchRequestException, RemoteTimeoutException, RemoteSendRequestException {
        super.invokeOnewayImpl(channel, request, timeoutMillis);
    }


    @Override
    public void shutdown() {
        try {
            if (this.timer != null) {
                this.timer.cancel();
            }

            this.eventLoopGroupBoss.shutdownGracefully();

            this.eventLoopGroupWorker.shutdownGracefully();

            if (this.nettyEventWorker != null) {
                this.nettyEventWorker.shutdown();
            }

            if (this.defaultEventExecutorGroup != null) {
                this.defaultEventExecutorGroup.shutdownGracefully();
            }
        } catch (Exception e) {
            log.error("NettyRemotingServer shutdown exception, ", e);
        }

        if (this.publicExecutor != null) {
            try {
                this.publicExecutor.shutdown();
            } catch (Exception e) {
                log.error("NettyRemotingServer shutdown exception, ", e);
            }
        }
    }

    @Override
    public ExecutorService getCallbackExecutor() {
        return this.publicExecutor;
    }

    class NettyServerHandler extends SimpleChannelInboundHandler<RemoteCommand> {

        @Override
        protected void channelRead0(ChannelHandlerContext ctx, RemoteCommand msg) throws Exception {
            processMessageReceived(ctx, msg);
        }
    }

    class NettyConnectManageHandler extends ChannelDuplexHandler {
        @Override
        public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
            final String remoteAddress = RemoteHelper.parseChannelRemoteAddr(ctx.channel());
            log.info("NETTY SERVER PIPELINE: channelRegistered {}", remoteAddress);
            super.channelRegistered(ctx);
        }


        @Override
        public void channelUnregistered(ChannelHandlerContext ctx) throws Exception {
            final String remoteAddress = RemoteHelper.parseChannelRemoteAddr(ctx.channel());
            log.info("NETTY SERVER PIPELINE: channelUnregistered, the channel[{}]", remoteAddress);
            super.channelUnregistered(ctx);
        }


        @Override
        public void channelActive(ChannelHandlerContext ctx) throws Exception {
            final String remoteAddress = RemoteHelper.parseChannelRemoteAddr(ctx.channel());
            log.info("NETTY SERVER PIPELINE: channelActive, the channel[{}]", remoteAddress);
            super.channelActive(ctx);

            if (NettyRemoteServer.this.channelEventListener != null) {
                NettyRemoteServer.this.putNettyEvent(new NettyEvent(NettyEventType.CONNECT, remoteAddress
                        .toString(), ctx.channel()));
            }
        }


        @Override
        public void channelInactive(ChannelHandlerContext ctx) throws Exception {
            final String remoteAddress = RemoteHelper.parseChannelRemoteAddr(ctx.channel());
            log.info("NETTY SERVER PIPELINE: channelInactive, the channel[{}]", remoteAddress);
            super.channelInactive(ctx);

            if (NettyRemoteServer.this.channelEventListener != null) {
                NettyRemoteServer.this.putNettyEvent(new NettyEvent(NettyEventType.CLOSE, remoteAddress
                        .toString(), ctx.channel()));
            }
        }


        @Override
        public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
            if (evt instanceof IdleStateEvent) {
                IdleStateEvent evnet = (IdleStateEvent) evt;
                if (evnet.state().equals(IdleState.ALL_IDLE)) {
                    final String remoteAddress = RemoteHelper.parseChannelRemoteAddr(ctx.channel());
                    log.warn("NETTY SERVER PIPELINE: IDLE exception [{}]", remoteAddress);
                    RemoteUtil.closeChannel(ctx.channel());
                    if (NettyRemoteServer.this.channelEventListener != null) {
                        NettyRemoteServer.this.putNettyEvent(new NettyEvent(NettyEventType.IDLE,
                                remoteAddress.toString(), ctx.channel()));
                    }
                }
            }

            ctx.fireUserEventTriggered(evt);
        }


        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
            final String remoteAddress = RemoteHelper.parseChannelRemoteAddr(ctx.channel());
            log.warn("NETTY SERVER PIPELINE: exceptionCaught {}", remoteAddress);
            log.warn("NETTY SERVER PIPELINE: exceptionCaught exception.", cause);

            if (NettyRemoteServer.this.channelEventListener != null) {
                NettyRemoteServer.this.putNettyEvent(new NettyEvent(NettyEventType.EXCEPTION, remoteAddress
                        .toString(), ctx.channel()));
            }

            RemoteUtil.closeChannel(ctx.channel());
        }
    }


    @Override
    public void registerRPCHook(RPCHook rpcHook) {
        this.rpcHook = rpcHook;
    }


    @Override
    public RPCHook getRPCHook() {
        return this.rpcHook;
    }


    @Override
    public int localListenPort() {
        return this.port;
    }

    @Override
    public Pair<NettyRequestProcessor, ExecutorService> getProcessorPair(int requestCode) {
        return processorTable.get(requestCode);
    }
}
